In prior art, devices are known to control the pivoting of the light beam of a right head-light and a left headlight of a vehicle, based on first information, such as based on the speed, the yaw rate, and the angle of the steering wheel (dynamic curve light). These devices improve both the illumination as well as visibility in roads with many curves. The use of first information, also called vehicle information, has proven disadvantageous, particularly when driving through curves and exits, because the pivotal angle of the headlights is only dynamically adjusted when the vehicle is already driving through curves or an exit.
In order to improve this situation, the so-called predictive curve light has been developed, in which the second information is used to adjust the light beam of the head-lights in a predictive fashion. The predictive headlight solves the problem of the dynamic curve light, which may develop for example when driving through curves or exits, because the headlights of the predictive curve light are always adjusted to the predictive pivotal angle.
Methods known today may lead to a maximum faulty adjustment of the predictive pivoted headlights in case of faulty information regarding the road progression. The consequences are an increased risk of blinding oncoming traffic, an illumination of the road traveled, which is not ideal, and a rising risk for accidents because the driver may be unnecessarily irritated and distracted by severely maladjusted headlights.
Furthermore, in methods known from prior art it is possible that at the transition between purely dynamic pivoting and purely predictive pivoting a (“cross-eyed”) interference of the light beams can occur on the road. This effect is undesirable for optic reasons.
Another disadvantage in methods of prior art comprises that the driver, unlike in dynamic curve light, cannot influence the direction of pivoting of the headlights in the predictive pivoting. In practice this may lead to the predictive pivoted headlight reaching its maximally possible pivotal angle before the driver starts driving through the curve. This means, at the moment the driver moves the steering wheel no reaction occurs in the illumination because the headlights have already reached their maximally possible pivotal angle by the predictive adjustment. This is unusual for the driver and may reduce the acceptance of the system.
Further, devices are known by which both a dynamic as well as a predictive pivotal angle can be adjusted. Such a device is known for example from the document DE 10 2005 036 948 A1. From the document DE10 2005 036 948 A1 second information is used, such as curvature and/or curve radius and/or curve direction in addition to first information, for example the present speed and/or the present angle of the steering wheel, in order to determine the predictive and dynamic pivotal angle. Additionally, static and/or distance-related and/or speed-related start and end points of curves are required as control aids for the activation/deactivation and/or transitions between the adjustment of the dynamic and/or the predictive pivoting angle. The document DE 10 2005 036 948 shows, among other things, several options of how various predictive and dynamic pivotal angles can be selected for headlights. In one option a predictive pivotal angle is initially set without limits. When the dynamic pivotal angle fails to reach the predictive pivotal angle, e.g. after a predetermined period of time, the predictive pivotal angle is successively reduced to the dynamic pivotal angle, i.e. limited. The successively limited predictive pivotal angle is sent as a control parameter to the headlights.
Disadvantages of this method as well as other methods and devices for combining dynamic and predictive curve light are:                When the predictive pivotal angle is flawed, the predictive pivotal angle is always selected initially with the potentially maximum error and converted into a control parameter for the headlight. The correction then only occurs when the dynamic pivotal angle fails to approach the predictive pivotal angle within a de-fined period of time. Until this correction is made, the driver is provided with less light than possible, particularly in case of maximum errors.        The driver has no option, in selected predictive pivotal angles, particularly when entering a curve and/or leaving a curve as well as during corrective motions (e.g. when avoiding an obstacle) inside a curve to move the adjusted pivotal angle further into and/or out of the curve via steering motions. Thus, the driver has no influence upon the light on the road in front of him/her and particularly in dangerous situations in which the driver must deviate from the predicted road progression the light is not provided where the driver needs it, but in the predicted driving direction.        